When the Gospel summarizes the triumph of Easter in the seven short words, “Christ was raised up from the dead,” they regard the mysterious but magnificent bursting of the grave an an unquestionable, supreme truth. There is never debate in the New Testament of the resurrection victory. Throughout the early church the declaration that “on the third day He rose again from the dead” is uncompromisingly accepted as the great climax truth of our faith.
No resurrection, no redemption.
No open grave, no opened heaven.
This is the unavoidable alternative: 1 Corinthians 15:14-18
And if Christ has not been raised, our preaching is useless and so is your faith. 15 More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead. But he did not raise him if in fact the dead are not raised. 16 For if the dead are not raised, then Christ has not been raised either. 17 And if Christ has not been raised, your faith is futile; you are still in your sins. 18 Then those also who have fallen asleep in Christ are lost.